Roof Problems - what to check before making an offer on a house?

Not all roof issues are obvious and repairing or replacing a roof can be expensive. Make sure you check these key points before making an offer on a property.

Will the property need a new roof or just a few repairs?

There are a number of factors that can affect the durability and overall lifespan of a roof.

Clues that a property you are thinking of buying may have problems with the roof include damp patches on the ceiling, stained plaster on the walls of the upper floors and sagging plaster ceilings. These may be noticeable when viewing the property.

Look at the roof from outside

During the viewing, try to get a good look at the roof. Cracked or dislodged tiles, loose mortar and torn lead flashing could all mean further problems. Take a pair of binoculars to the viewing to get a closer look at the roof externally.

Look for any gaps in the tiling, on both the roof's slope and along the ridge. Although replacing individual tiles should not be costly, you may have to consider more expensive repairs if there are several damaged areas.

Lead flashing (used to seal between roof tiles and brickwork) will need repairing if it is torn. Pay close attention to signs of damage to chimney stacks, single-storey extensions and the valley where the two sections of sloping roof meet.

Check the fascia boards are intact. Fascia boards are usually fixed to the lower ends of the roof trusses and they give support to the bottom row of roof tiles. Damaged or rotten fascias will need replacing.

Look at the gable end of the roof where the verge tiles are finished off with cement. If there has been water ingress this may have cracked the cement bedding, causing it to flake and crumble away.

Get up in the loft

If you can check inside the loft space during the day for spots of light as these indicate missing mortar and tiles or damaged flashing. Take a torch so you can look in the loft space to examine the roofing felt and the trusses for signs of deterioration.

Talk to the seller

Ask the seller if the roof has been repaired or replaced, either in part or whole. Ask whether there any certificates or guarantees.

What is the average lifespan of a roof?

High winds, frost, snow and heavy rain will gradually take their toll on any roofing material.

The Sun is particularly damaging to flat asphalt roofs. Although excessive sunshine is not a primary concern in the UK, recent record temperatures could lead to surface cracking.

Strong winds and heavy rain can lead to missing or broken tiles and water ingress. Coastal properties are particularly prone to these conditions.

Ultimately the lifespan of the roof will depend on the type of material used:

Does the property have a flat roof?

Garages and outbuildings commonly have flat roofs, as do some single-storey extensions. They are typically covered in felt (asphalt), although newer roofs may be made of longer-lasting EPDM rubber.

Asphalt roofs tend to have a lifespan of 10-25 years, although this varies with factors like the weather. EPDM roofs can last up to 60 years.

Flat roofs can be damaged by falling branches or by walking on them. Damp patches on a ceiling may be a sign of a tear in the roofing material. Check outside for cracks and splits and uneven lumps.

Check that the roof completely flat. A sagging roof can hold water and the weight can cause the supporting boards to break.

How much will a replacement roof cost?

Replacing the entire pitched roof on an average 3-bedroom house should cost between £5,500 and £8,500. Expect to pay more for a slate roof as the materials are generally more expensive.

A typical 6m x 3m flat roof is likely to cost about £1,200 to replace.

A Homebuyer Report or Building Survey will identify roof defects. If the surveyor does find problems with the roof, you could get a couple of estimates for the repairs and use these as the basis of renegotiation with the seller.

See also:

What to check before buying a house with solar panels